The present invention relates to a radiation image detecting system having the radiation image receiving plane constituted of a plurality of two-dimentionally arrayed radidation sensors.
In a typical example of the system for electronically detecting a radiation image with the image divided into pixels, the number of pixels often reaches the order of 10.sup.6, provided that a typical image receiving area of 30.times.30 cm.sup.2 is required with the pixels having a very small irradiation area of the order of 10.sup.-1 mm.sup.2 to comply with a required resolving power of image detection. In such a case it makes the system very complex and expensive to provide such a numerous number 10.sup.6 of radiation sensors in correspondence to the number of pixels.
A possible conventional measure to overcome the above disadvantage and difficulty is to scan the imaginary plane of image receiving with a single radiation sensor two-dimensionally or with a series of linearly arrayed radiation sensors one-dimensionally (in the direction vertical to the array). However, such a scanning method by a single sensor or arrayed sensors has a decisive disadvantage that not only it takes a long time to complete the scanning over the entire area of the image receiving plane, but also the efficiency of radiation detection is very low because the radiation irradiating the image receiving plane is wasted except for a successively traveling spot or linear region where the scanning single sensor or sensor array is being irradiated. Suppose the case where a series of n linearly arrayed sensors one-dimentionally scans the entire area of an image receiving plane divided into n.times.n pixels, the efficiency of radiation detection is 1/n. In case where the same area is two-dimansionally scanned by a single sensor, the efficiency is further decreased to 1/n.sup.2.